Themap1Gene ofCowdria ruminantiumIs a Member of a Multigene Family Containing Both Conserved and Variable Genes

Sulsona, Carlos R.; Mahan, Suman M.; Barbet, Anthony F.

doi:10.1006/bbrc.1999.0459

Cited by 45 publications

(26 citation statements)

References 36 publications

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“…For instance, bacteria of the genus Borrelia generate antigenic diversity of the vmp͞vls coat proteins through recombination from a tandem array of silent partial pseudogene cassettes into a telomeric expression site on a linear plasmid (1, 2). Ehrlichial genogroup I pathogens, Ehrlichia chaffeensis, E. canis, and Cowdria ruminantium, have recently been shown to contain tandemly repeated copies of the omp1͞map1 gene family (3)(4)(5)(6). These omp1͞map1 tandem repeats are complete gene copies, and multiple copies may be transcriptionally active at a given time, resulting in polymorphic protein expression (3).…”

Section: Biochemistry For the Article ''Functional Transitions In Mymentioning

confidence: 99%

Efficient use of a small genome to generate antigenic diversity in tick-borne ehrlichial pathogens

Brayton

Knowles

McGuire

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

127

154

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Ehrlichiae are responsible for important tick-transmitted diseases, including anaplasmosis, the most prevalent tick-borne infection of livestock worldwide, and the emerging human diseases monocytic and granulocytic ehrlichiosis. Antigenic variation of major surface proteins is a key feature of these pathogens that allows persistence in the mammalian host, a requisite for subsequent tick transmission. In Anaplasma marginale pseudogenes for two antigenically variable gene families, msp 2 and msp 3, appear in concert. These pseudogenes can be recombined into the functional expression site to generate new antigenic variants. Coordinated control of the recombination of these genes would allow these two gene families to act synergistically to evade the host immune response.

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Section: Biochemistry For the Article ''Functional Transitions In Mymentioning

confidence: 99%

Efficient use of a small genome to generate antigenic diversity in tick-borne ehrlichial pathogens

Brayton

Knowles

McGuire

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

127

154

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“…Multigene families encoding for outer membrane proteins have been identified in the genus Ehrlichia and designated P28 (OMP-1) in Ehrlichia chaffeensis, P30 in Ehrlichia canis and the major antigenic protein 1 (MAP1) family in E. ruminantium (Ohashi et al, openUP (July 2007) 1998a, Ohashi et al, 1998b andSulsona et al, 1999). These genes are thought to be responsible for adaptation to the environment in the tick and involved in transmission to the mammalian host (Felek et al, 2003 andUnver et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Differential transcription of the major antigenic protein 1 multigene family of Ehrlichia ruminantium in Amblyomma variegatum ticks

Postigo

Taoufik

Bell‐Sakyi

et al. 2007

Veterinary Microbiology

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The rickettsial pathogen Ehrlichia ruminantium causes heartwater in ruminants and is transmitted by ticks of the genus Amblyomma. The map1 gene, encoding the major surface protein MAP1, is a member of a multigene family containing 16 paralogs. In order to investigate differential transcription of genes of the map1 multigene family in vivo in unfed and feeding ticks, RNA was extracted from midguts and salivary glands of E. ruminantium-infected adult female Amblyomma variegatum ticks and analysed by RT-PCR using MAP1 paralog-specific primers. In unfed ticks, only transcripts from the map1-1 gene were observed in midguts and no transcripts were detected in salivary glands. In feeding ticks, map1-1 transcripts were more abundant in midguts whereas high levels of map1 transcripts were observed in salivary glands. Our results show that differential transcription of genes of the E. ruminantium map1 cluster occurs in vivo in different tissues of infected ticks before and during transmission feeding, indicating that openUP this multigene family may be involved in functions of biological relevance in different stages of the life cycle of E. ruminantium.

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“…The genes coding for these proteins have been designated the major antigenic protein 1 (map1) in E. ruminantium (32,40), the outer membrane protein p28 (omp-1) in E. chaffeensis, and the p30 outer membrane protein (p30) in E. canis (27,28,30,35,36,42,43). The OMP-1 and P30 protein families are each encoded by a multigene family consisting of 22 genes arranged in a cluster between a hypothetical transcriptional regulator (upstream) and the secA gene (downstream).…”

mentioning

confidence: 99%

Transcription Analysis of the Major Antigenic Protein 1 Multigene Family of Three In Vitro-Cultured Ehrlichia ruminantium Isolates

et al. 2005

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Ehrlichia ruminantium, an obligate intracellular bacterium transmitted by ticks of the genus Amblyomma, causes heartwater disease in ruminants. The gene coding for the major antigenic protein MAP1 is part of a multigene family consisting of a cluster containing 16 paralogs. In the search for differentially regulated genes between E. ruminantium grown in endothelial and tick cell lines that could be used in vaccine development and to determine if differences in the map1 gene cluster exist between different isolates of E. ruminantium, we analyzed the map1 gene cluster of the Senegal and Gardel isolates of E. ruminantium. Both isolates contained the same number of genes, and the same organization as found in the genome sequence of the Welgevonden isolate (H. Van Heerden, N. E. Collins, K. A. Brayton, C. Rademeyer, and B. A. Allsopp, Gene 330:159-168, 2004). However, comparison of two subpopulations of the Gardel isolate maintained in different laboratories demonstrated that recombination between map1-3 and map1-2 had occurred in one subpopulation with deletion of one entire gene. Reverse transcription-PCR on E. ruminantium derived mRNA from infected cells using gene-specific primers revealed that all 16 map1 paralogs were transcribed in endothelial cells. In one vector (Amblyomma variegatum) and several nonvector tick cell lines infected with E. ruminantium, transcripts were found for between 4 and 11 paralogs. In all these cases the transcript for the map1-1 gene was detected and was predominant. Our results indicate that the map1 gene cluster is relatively conserved but can be subject to recombination, and differences in the transcription of map1 multigenes in host and vector cell environments exist.Ehrlichia ruminantium (formerly Cowdria ruminantium [12]) is the causative agent of heartwater, a rickettsial disease transmitted by ticks of the genus Amblyomma which causes major economic losses in wild and domestic ruminants. The disease is endemic in sub-Saharan Africa and also is present on some Caribbean islands (33), where it poses a risk of spreading to the American mainland. Feeding ticks transmit E. ruminantium to vertebrate hosts in their saliva and/or by gut regurgitation (8,19). Phylogenetic studies have revealed a close relationship between E. ruminantium, Ehrlichia canis, and Ehrlichia chaffeensis (30,39).In infections with these ehrlichial agents, the serological response is mainly directed against outer-membrane proteins of approximately 30 kDa. The genes coding for these proteins have been designated the major antigenic protein 1 (map1) in E. ruminantium (32,40), the outer membrane protein p28 (omp-1) in E. chaffeensis, and the p30 outer membrane protein (p30) in E. canis (27,28,30,35,36,42,43). The OMP-1 and P30 protein families are each encoded by a multigene family consisting of 22 genes arranged in a cluster between a hypothetical transcriptional regulator (upstream) and the secA gene (downstream). The 5Ј end of the cluster contains paralogs with short intergenic spaces, whereas the paralogs at t...

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Themap1Gene ofCowdria ruminantiumIs a Member of a Multigene Family Containing Both Conserved and Variable Genes

Cited by 45 publications

References 36 publications

Efficient use of a small genome to generate antigenic diversity in tick-borne ehrlichial pathogens

Efficient use of a small genome to generate antigenic diversity in tick-borne ehrlichial pathogens

Differential transcription of the major antigenic protein 1 multigene family of Ehrlichia ruminantium in Amblyomma variegatum ticks

Transcription Analysis of the Major Antigenic Protein 1 Multigene Family of Three In Vitro-Cultured Ehrlichia ruminantium Isolates

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